The present invention relates generally to the field of measurement of fluid flow velocity; more particularly, the invention was developed originally for use in a system which measures the velocity of fluid flow by photographing the displacements of fine (micron sized) particles using multiple exposures from a pulsed laser. The background or context from which the invention sprang may therefore be characterized as instrumentation for fluid flow measurement.
More generally, the invention may be said to pertain to any image processing problem in which the displacements of many discrete images are to be measured, including the motion of solids. In the description that follows the invention will be considered primarily in the context of fluid flow measurements.